Most medications can cause side effects which can be defined as an unwanted response to a medication when it is taken in normal doses. Side effects can range from mild or severe, temporary or permanent. Side effects are not experienced all patients who take this medication. Many side effects can be managed, and others may go away over time. Common side effects may include nervousness, difficulty falling asleep or staying asleep, upset stomach, dry mouth, sore throat, drowsiness, weakness, shaking hands that you cannot control, loss of appetite, weight loss, changes in sex drive or ability and excessive sweating. Serious side effects may include: severe blistering, peeling, and red skin rash, very stiff (rigid) muscles,, high fever, fast or uneven heartbeats, tremors, overactive reflexes, nausea or vomiting, diarrhea, loss of appetite, feeling unsteady, loss of coordination, headache, trouble concentrating, memory problems, weakness, fainting, confusion, hallucinations, seizure, shallow breathing or breathing that stops Get emergency medical attention if you have any signs of an allergic reaction (hives; difficulty breathing; swelling of your face, lips, tongue, or throat). Stop using PROZAC immediately and call your doctor at once if you experience any of the above noted serious side effects. Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself. This is not a complete list of side effects and others may occur. Call your doctor for medical advice about additional side effects that you may experience.